Application value of contrast-enhanced transrectal ultrasound in differential diagnosis of benign and malignant prostate nodules

Objective To investigate the application value of contrast-enhanced transrectal ultrasound (CE-TRUS) in differential diagnosis of prostate benign and malignant lesions. Methods A retrospective analysis of patients with prostate lesions detected by CE-TRUS from January 2014 to December 2016 in Southwest Hospital of Third Military Medical University was performed. Seventy-two cases of prostate disease with 88 lesions were confirmed by transrectal prostate biopsy under ultrasound guidance. The age of patients with benign and malignant lesions, serum prostate specific antigen (PSA), and the size of prostate and prostate inner gland were compared by independent sample t test. Pathologic results of transrectal prostate biopsy under ultrasound guidance were used as diagnostic gold standard, and the sensitivity, specificity and accuracy of CE-TRUS in diagnosis of benign and malignant prostate lesions were calculated. Results Sixty-seven lesions in 52 patients were benign prostatic diseases, and 21 lesions in 20 patients were prostate cancer in this study. The size of prostate and prostate inner gland were not different between patients with prostate cancer and benign prostatic diseases [(58.33±34.99) cm3 vs (57.14±24.42) cm3, t=0.185, P=0.854; (34.98±19.96) cm3 vs (33.89±17.65) cm3, t=0.213, P=0.832]. Most of prostate cancer lesions were in prostate outer gland area (15/21), and contrast-enhanced ultrasound imaging showed contrast enhancement increased mostly in arterial phase and faded faster than the surrounding tissues (16/21). However, most of prostate benign lesions were in prostate inner gland (47/67), and contrast-enhanced ultrasound imaging showed contrast enhancement was mostly equal with the surrounding tissue in arterial phase and faded the same as the surrounding tissues in venous phase (47/67). Pathologic results of transrectal prostate biopsy under ultrasound guidance were used as diagnostic gold standard, the sensitivity of CE-TRUS in diagnosis of benign and malignant prostate lesions was 85.71%, the specificity was 91.04%, and the accuracy was 89.77%. Two lesions were in prostate inner and outer gland border areas in the three missed prostate cancer lesions, and Gleason scores were all medium and high differentiated group. Six prostate benign lesions were diagnosed as malignant lesions, five lesions were confirmed prostate hyperplasia with chronic prostatitis and one was confirmed granulomatous inflammation with coagulation necrosis by transrectal prostate biopsy under ultrasound guidance. Conclusion CE-TRUS can effectively identify prostate benign and malignant lesions, and provides reliable information for accurate diagnosis of prostate cancer. Key words: Prostatic neoplasms; Ultrasonography; Contrast media; Diagnosis, differential